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On Thu, 13 Mar 2003, Phil Barker wrote: > 1.1.1 Catalog (re Andy's comments) > Any chance of someone like JISC setting up a Handle registry? Does it come > within the scope of the JISC call 5/03 > (http://www.jisc.ac.uk/index.cfm?name=funding_5_03) That is certainly worth thinking about... but I don't think it falls under the scope of that particular call (which is primarily targetted at getting 'publishers' to adopt some of the technologies specified in the IE technical architecture). Again, I think it is worth thinking about the functional requirement here... So, in the context of X4L (but assuming that any X4L requirement is likely to be a requirement more generally) do we want to be able to: 1) assign unique, persistent identifiers to learning objects (and parts thereof) 2) resolve the identifier (i.e. enter the identifier or a modified form of the identifier into our browser 'Address' bars and be directed) to the current location of the object or both of these? I'm going to assume that the requirement is for both. Shout if it isn't! OK. I'm going to suggest that DOIs, Handles and PURLs would all meet both requirements. Of these, DOIs and Handles have the slight advantage that they are not tied to the HTTP protocol and that they are underpinned by a properly distributed database technology). Any form of URI other than 'http', 'ftp', etc. would only meet requirement 2 if we could develop an associated 'resolver' service. In the OAI world, requirement 1) has been met by the use of 'oai' URIs to identify each 'item' in OAI repositories. An example URI is oai:rdn.ac.uk:12345-67890 The 'oai' part says this is an 'oai' URI, i.e. it conforms to the 'oai' URI scheme. The 'rdn.ac.uk' bit says that this URI was assigned by the RDN. The '12345-67890' part is an identifier that is unique within the RDN. Overall, uniqueness is guaranteed (as long as the 'rdn.ac.uk' part is unique - which is why the use of DNS domains for this part is strongly encouraged). At the moment, there is no 'resolver' service for 'oai' URIs. If I type 'oai:rdn.ac.uk:12345-67890' into my browser Address bar I'll get an error - because my browser doesn't understand the 'oai' URI scheme. One could build a resolver service for these URIs by harvesting metadata records from all known OAI repositories and building a list of all 'oai' URIs and their associated URLs (possibly taken from the metadata record for that item). As far as I know, no-one has done this yet - but it would be quite a neat idea. Then one would need a technology for actually doing the resolution. It would be possible to use either the Handle system or the PURL system for this. For example, one could register all the 'oai' URIs with the PURL resolver at http://purl.org/ using a convention like http://purl.org/oai/oai:rdn.ac.uk:12345-67890 This would be pretty trivial to do. Doing so would allow people to actually use the 'oai' URIs to link to things. Doing something similar with the handle system would, I think, be fairly straight-forward. OK, so here's my suggestion. We find an existing URI scheme (or if absolutely necessary invent our own one) that, like the 'oai' scheme, allows us to idependently assign unique identifiers to learning objects. We then build a resolver service for those URIs using the PURL or Handle systems. (Initially, we would not actually run a copy of the PURL or Handle resolver software locally in the UK - but longer term we could think about doing that if performance issues deemed it necessary). If we could assume that all learning object repositories were going to expose their metadata using the OAI-PMH, then we could do this by using the 'oai' URI scheme. That would be my preferred approach. Clearly, even without the need to run our own resolver, there is still a need to register the 'oai' URIs that we assign with the PURL resolver - this would have to be undertaken centrally, based on regular OAI harvesting. Therefore this would have to be a funded 'service'. Therefore someone would have to make a proposal to JISC (or whoever) to run this service. The advantage of this approach is that, assuming that we can agree to it in principle, we can start assigning 'oai' identifiers now, without waiting for the resolver to be deployed. I.e. we meet requirement 1) in the short term and requirement 2) in the medium term? Comments? Andy -- Distributed Systems, UKOLN, University of Bath, Bath, BA2 7AY, UK http://www.ukoln.ac.uk/ukoln/staff/a.powell +44 1225 383933 Resource Discovery Network http://www.rdn.ac.uk/